1. Field of the Invention
The present invention relates to an image forming apparatus that continues the conveyance of a recording sheet without stopping the apparatus even if there is a failure in the conveyance of the recording sheet and then discharges the recording sheet remaining in the apparatus, thereby making it possible to implement a printing operation in a short period of time.
2. Description of the Related Art
In general, a known copier has, for example, an annular sheet conveyance path for double-sided printing. In such a copier, if a conveyance failure occurs along on the sheet conveyance path, it is necessary to temporarily stop the image forming apparatus and remove all the recording sheets circulating in the apparatus.
In the copier described in Patent Document 1, a recording sheet having been subjected to double-sided printing is specified from among those remaining in the apparatus when jamming occurs and then discharged if the recording sheet is determined not to be a jammed sheet. In other words, when jamming occurs along on a conveyance path in the copier described in Patent Document 1 that performs double-sided printing while circulating plural of the recording sheets on the conveyance path, a recording sheet to be discharged is determined based on the discharge destination information of the recording sheet (i.e., information indicating whether the recording sheet is to be discharged outside the apparatus or conveyed to an inversion path) and the positional information of the recording sheet on the conveyance path. That is, when it is determined that jamming is not caused based on the jamming information on the recording sheet, the recording sheet is discharged outside the apparatus. Thus, the unnecessary use of the available recording sheet having been subjected to printing can be prevented.
Furthermore, in a recording apparatus described in Patent Document 2, a determination is made as to whether a recording sheet is deflected or skewed on a conveyance path. When the determination result does not fall within a specified range, the recording sheet is guided in a direction different from a normal sheet feeding/discharging direction and removed from the conveyance path, thereby reducing the occurrence of jamming.    Patent Document 1: JP-A-2002-268304    Patent Document 2: JP-A-56-8163
However, Patent Document 1 only describes that an available recording sheet determined not to be a jammed sheet is discharged even if jamming occurs for the purpose of preventing the unnecessary use of the available recording sheet having been properly subjected to printing.
Furthermore, Patent Document 2 only describes that a deflected or skewed recording sheet is immediately removed from the conveyance path for the purpose of preventing the occurrence of jamming on the conveyance path for the recording sheet.
On the other hand, the user, who performs large amounts of printing such as printing of 90 sheets per minute, not only requests for a high printing speed but also wishes to perform a restoration process in the shortest time possible when an apparatus is stopped due to a failure in the conveyance of a recording sheet.